Plaster-board composition.



. claims.

MORGAN K. STRONG, OF

MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS,

WINNE'IKA,-ILLINOIS, ASSIG-NOR T0 BESTWALL A CORPORATION OFSpecification of Letters Patent. P t t 19 g To all whom it may concern.-

Be it known that I, MORGAN K'. ARM- STRONG, a citizen of the UnitedStates, and a resident of Winnetka, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements in Plaster-Board Compositions; and I do hereby declare that. the following is afull, clear, and exact description thereof.

This invention relates to plastic composition and consists of tershereinafter described and more particularly pointed out in the appendedimprovements in 'The object of the invention is the production of aplastic composition more particularly adapted as a filler for plasterboard consisting of covering sheets of paper or other fibrous materialand of an intermediate plastic body. The composition, however, isequally useful for other purposes where its peculiar characteristicsmake its use advantageous.

My improved composition consists of a mixture of dry, ground tan bark,of gypsum or stucco, plaster of Paris or like plastic material.

In preparing the composition, I prefer to use the ingredients inapproximately the following proportions :-fifteen pounds of ground tanbark and eighty-five pounds of stucco, or other suitable calcinedgypsum,

' The tan bark and gypsum plastic material.

' are thoroughly mixed, and to each one hunthis dry mixture is addeddred pounds of about thirty pounds of water. The water, if

slightly warmed, will more-readily mix with the dry ingredients. a

I prefer to mix the dry, and gypsum in'a hopper or other vice'and thenvdischarge this dry ground tan bark mixingdemixture in a thin, flat,even layer upon a movable belt.

I 9.180 prefer to introduce the water into the dry mixture 'while ontime stirring them together.

Under someweather conditions, when low temperatures prevail, I find itadvantageous to add to the dry mixture, a hastener or accelerator suchas dextrin or like material, in about the proportion of twenty-fivepounds of hastener, to about twelve hundred pounds Of the drymixture oftan ba k d m,

the matterial, as fortinstance,

the belt, at the same F v proximately eighty-five gypsum, mixed dry withapproximately fifbecause the tan bark includes particles much finer thansawdust.- Thus, a larger proportion of tan bark can be used in thecomposition. instead of sawdust, without reducing the resistance againstfracture in the finished and set composition as if saw dust had,

been used. Hence tan bark makes an exceptionally good alternative orsubstitute for sawdust in a plastic composition.

The small percentage of tannic acid remaining in the ground tan bark,after it has been used in a tannery, acts as an a erator to the settingor hardening of the fillished composition when used for any purpose.

My improved composition is light in weight, is fireproof, is anefiicient non-conductor of heat, is'impervious to the action of water,after having set and it, adheres to the surfaces to which it is appliedand possesses all the desirable properties of a plastic composition tobe used as a filler for wall board, and for such other purposes. as itis desired to use the same.

In describing my invention, I have set forth gypsum or stucco as one ofthe ingredients, but I use these 'terms as meaning any dry, pulverizedplastic equivalent maplaster Paris. I claim as my invention: 1. Aplastic composition comprising appounds of calcined teen pounds ofground tan bark, thecombinedone hundred pounds of dry mixture beingagain mixed with substantially thirty pounds of water.

2.-A plastic composition "comprising approximately eighty five pounds-pfcalcined gypsum, approximately fifteen pounds of as my invention, Iafli'x my signature in the ground tan bark, and approximately twopresence of two witnesses, this 13th day of poundsof hastener, mixeddry, the combined March, A. D. 1918.

dry mixture having added to 11; about thirty MORGAN K. ARMSTRONG. 5pounds of water for approximately each Witnesses:

one hundred pounds of dry mixture. T. H. ALFREns,

In testimony that I claimthe foregoing D. DARRENOUGUE.

